GENEX Project: Optimizing the operation of electric hydrogenerators

GENEX Project: Optimizing the operation of electric hydrogenerators

Project director: Eng. Vintila Adrian

The production of electricity is almost entirely done with the help of synchronous generators. These are medium and high power electrical machines. They have a long operating life of about 30 years. After this time they are completely rehabilitated. Operation with maximum energy efficiency is absolutely essential. Also, reliability in supplying the networks is a major requirement.

Most synchronous generators in the country use old rotary exciters. These operate as DC generators or with rotating diodes. Only a few national units have implemented static excitation variants. In recent years, there has been a special emphasis on modernization. We want to modernize the excitation systems in order to achieve superior performance. In this way, we comply with the regulations imposed by the Community Union and TRANSELECTRICA.

Our priority is research into static excitation systems. These are designed for hydrogenerators with unique characteristics. They have high electromagnetic constants and very large inertial masses. These parameters can lead to dangerous overvoltages in transient regimes. The project aims at the theoretical and experimental study of modern systems. We use digital regulation to increase efficiency and automation.

The project is in line with current European research. We are developing high-performance digital control systems and new strategies. We use advanced static excitation systems as an execution element. We aim to reduce dangerous overvoltage peaks in the system. We are developing modern de-excitation and forcing excitation modules. These ensure extremely high response speeds in operation.

Theoretical study and numerical modeling

• Study on the current state of research in this field;
• Analysis of the structure of existing systems, limits, disadvantages and trends;
• Study of static excitation systems and automation possibilities;
• Creation of a numerical model using internationally recognized software products;
• Use of specialized software platforms such as Matlab and Simulink;
• Studying operating regimes to crystallize optimal technical requirements.

Design, experimentation and implementation

• Analysis of network functions and dynamic performances;
• Establishing the characteristics of the hardware system (programmable logic controller, DSP development);
• Choosing an optimal static excitation solution for the experimental model;
• Elaboration of the technical specification and complete execution documentation;
• Creation of an experimental laboratory model with static excitation;
• Testing a 15 kVA salient pole synchronous generator;
• Carrying out complex tests and experimental studies on the model;
• Elaboration of a final report on the scientific results obtained;
• Dissemination of results and direct technological transfer to beneficiaries.

Future prospects and prototype development

It is clearly stated that this complex research project has as its practical realization a laboratory model and an industrial model. These will be continued in a later phase within another future partnership. The new partnership will strictly aim at the creation of a homologated prototype. For this reason, related to the prospects of developing applications in the field, the final report contains an additional element. It also includes in the summary a professional specification for the creation of a prototype.

The impact involved the technological transfer of the studied solutions directly to the hydropower plants. We also focused on hydropower plants that are currently under construction or in the rehabilitation phase. Of the total number of hydropower plants in the country, with an installed capacity of 6,400 MW, over 90% provide energy with outdated systems. These belong to the 124 large hydropower plants and 223 microhydropower plants. They have a low degree of automation and a very low energy efficiency. The equipment is completely incompatible with the modern energy system of the European Union. All these units have started or will immediately start the rehabilitation process.

The undeveloped hydropower potential is still estimated at a fabulous 5,600 MW. For this, the issue of modern solutions dedicated exclusively to excitations arises. The project determines a significant increase in the efficiency of energy production from non-polluting sources. It also encourages the development of applications in the field of medium or small power hydropower.

The impact was also strong on the national educational system. The Politehnica University of Timisoara (Faculty of Electrical Engineering) and the University of Craiova (Faculty of Electromechanics) were involved. Young specialists were trained, prepared to assimilate advanced technologies. They will develop modern energy production solutions. Finally, the hydropower plants will be correctly connected in a system fully compatible with European Union standards.

Document description	Download
Stage I (2007) – Analysis of solutions for modernizing electric hydrogenerator excitation	Download PDF
Stage II (2008) – Achievement of execution documentation for experimental model	Download PDF